A day after Applesued them over their App Store trademark, Amazon has gone ahead and launched their Amazon Appstore for Android anyway, allowing United States Android owners the ability to not only shop amongst 3,800 Android apps, but — today only, although other free apps will follow — download the latest Angry Birds games as well for free.

It’s a pretty impressive launch, truth be told: the Windows Phone 7 app market launched with significantly less titles, and couldn’t boast anywhere near the same developer support.

The coolest feature of the Amazon Appstore for Android? You don’t have to pay for an app to try it out. Instead, they’ve figured out a nifty way to embed an Android emulator into the browser, where you can play with it for thirty minutes. If you like the app, you can then buy it with just one click, provided you’re already signed up with Amazon for One-Click shopping.

From a user’s perspective, the big reason to use Amazon Appstore for Android instead of the Android Marketplace is because of Amazon’s incredible recommendation algorithm, which should allow users to get useful recommendations of similar titles to even the most esoteric apps through Amazon’s familiar “people who bought this also bought that” recommendation system.

There’s another reason to be excited about Amazon Appstore for Android if you’re an Android user, too: it’s curated. It’s a significantly better experience than Google’s own Android Market, in that Amazon is personally recommending each and every app before it goes on sale. Amazon’s not taking a censorship stand on these apps, either. It’s all about quality-assurance, meaning that if you download an Android app, you can be sure that it won’t blow up your phone or be a waste of $10 dollars.

Honestly, it’s pretty embarrassing for Google. When Amazon announced their Appstore, it seemed completely disposable, a WTF move. Yet even on day one, Amazon’s Appstore has already become more indispensible for Android users than the official Android Market. Jeez, Google.